OVERVIEW: There are several very useful web resources for help with your Tektronix scope or other instrument, even if it is 'Out of Support' at the factory. Full details are below, email if you have new ones to add!

Tektronix Web-based Support of all kinds Tektronix Gateway Page All kinds of useful information, including some manuals, but use the other manual sources identified here if you can't find what you want. Now mainly current product info only.Bill and Stan's site has all kinds of useful Tek info!This link takes you to their CRT/Instrument cross-reference, and you can navigate from there to many other great tools on their site, lots of unique data on older tube models and parts information.

W140.COM An excellent site hosting the Tekwiki, full of data on Tek models, specs, and pictures. Also manuals and related helpful data. Takes a few seconds to load the big gateway page, don't be alarmed!

The Open Source SG504 Leveling Head Project, Ancel's excellent replacement for the often missing or dead SG504 Leveling Head. Excellent flatness. We have two here, they work great. You can also contact him directly for kits and finished/tested units HERE.

The Bitsaver Massive Archive of Full Tektronix Catalogs, be sure you have your full bandwidth engaged for this visit! Covers 1953 to 1981, the really good years! Typical catalogs are 300Mb, so be patient! Remember, RIGHT CLICK to save the file, otherwise your browser will lock up trying to display the entire 300Mb file! A fantastic site for Tek fans.

David Partridge's Projects Some fascinating items, including an inexpensive NEW design for the always missing or broken SG504 leveling head, Tek 7T plug in tricks and more. Worth a visit! If you have ever been tempted to bid on a 1Ghz Tek SG504 generator, but didn't becuase the critical leveling head was missing, this site will solve your problems!

OVERVIEW: How many times have you wished there was a good general manual from Tektronix on how to troubleshoot and repair their scopes ?

May 25, 2004Well, as it turns out, such a manual actually exists, although clearly not many people have ever seen it!. It is quite exhaustive, with flowcharts and some useful schematic diagrams. It was printed in 1989, and is called: Troubleshooting Your Scope: getting down to basicsJust click on the title to download the 94 page (3.7Mb PDF file) book. It is clearly a scanned original someone sent to me a while ago, and I have just lost track of its origin. Whoever you were, many thanks on behalf of everybody working on Tek equipment, and to Tek for allowing the material to now be copied.

OVERVIEW: Tek 155 Series HybridsThese parts are all in-house designs, NOT outside vendor parts, no substitutes exist except for other 155 or 165 series parts in some cases. They are removable (except the horizontal output hybrid, which is soldered in) by removing the 4 corner nuts, and pulling the heatsinked hybrid away from the board socket. Blocked ventilation causes premature failures of these parts due to poor air circulation and elevated temperatures. Later production of these parts shifted to Maxim when Tektronix sold the chip foundry to them, those parts are marked Maxtek, early ones tend to be a problem while they learned how to make the parts, later ones work pretty well. There is very limited stock of the 155 parts worldwide, EMAIL SUSAN if you need something, she will tell you the current stock and availability status. We have managed to work some deals with other international service centers to pool parts and provide one stop support via our facility.

Date: May 13, 2004 From: Denis CobleyTek hybrid failures:By MODEL NUMBER: 2445B (above s/n B05 has the channel switch IC problem because it was made by
Maxtek - the Tek branded parts are fine)
All the hybrids do fail occasionally and I have noted the following most
common failures below:

2445/65 - Horz Output Hybrid (-00 + 01 beam is always to the left of
screen - first signs are Horizontal cursors both drift left on screen over time or
are offset to the left).

2445B/65B (above s/n B05) Channel Switch, this shows as compression at top and bottom of display or bandwidth drops to about 230MHz in the 2465B.

2445A - most reliable version - no common failures.By HYBRID TYPE: All can have the Z-Axis Hybrid fail - results in no display - so turn up the Grid Bias to see a display - you will also get lots of readout dots. Trigger hybrids - random - either total loss of triggering or poor
triggering.

Preamps - normally due to input overload - you can often measure a voltage at the
BNC center pin as the FET is punched through.

Dirty attenuators - 2445/65 + 2430 but will show up later in all models as they use the same basic attenuator - shows as gain problems or 50 ohm term
problems - the attenuator switches at 0.1V and 1V, - 2mV to 50mv are gain
switching by preamp.

Sweep Hybrids - Very rare, swap to confirm.

The Tek 155-0241-02 Re-Bake Program

Fixing 155-0241-02 Horizontal Driver ICs:

This part has been an ongoing source of trouble in all 24xx series models, and is the most requested 155 spare part. Unfortunately, they are simply no longer available, so we have a different method to address this problem. We can provide this service for users in North America, or others who
want to ship to us (but freight cost may be higher). Batches are done roughly once a quarter, depending on the quantity of available repair candidates.

The process essentially attempts reattachment of the main die to the
heatsink substrate, and is done at a semiconductor manufacturer's facility in Japan. Results
to date have been good on many chips (100's) and the success rate of
suitable candidates is approx. 70%. Any parts for re-work MUST be
professionally de-soldered with FULL CLEAN LEADS. If badly removed or
heat damaged further, there is no point in attempting repair, or in
sending the part to us.

This re-work is done in batches, and there must be a certain critical
number of parts in Japan before work can start. Individual parts can be added
to the batch in progress, but until at least 20 parts are collected,
no work will be done. Batches are run roughly every quarter, whether
parts from North America are ready or not, if late, they have to wait
for the next processing cycle.

What parts are suitable candidates?

Those with thermal failures, which work briefly at power up, then shut
down, or stop sweeping, some limited left/right position control must
still be present. They may have reduced scan, big timing errors on the
1ns and 2 ns ranges, or exhibit thermal latch up. Parts with
localized individualized pin failures of some sort or another or have
catastrophic output failure are NOT fixable by this method.

We cannot guarantee success, and approximately 5% of the fixed chips
will re-fail within a year, due to fundamental design issues. When
you pay to have your chip processed, and it is a suitable candidate,
the odds favor success, but reality indicates that it may not work, or
may fail again later. This is the limit of what is physically
possible, so be sure you understand it going in. We have had
excellent results with the repaired chips, as have many other customers.

Send all your parts to Sphere Research Corporation, 3394 Sunnyside
Rd., West Kelowna, BC, V1Z 2V4 CANADA. Airmail is fine, use a low
declared value ($10), as the parts are BROKEN. Payment is required
with the parts (can be US$ check, Visa/MC), and is US$70 per chip, and
US$21 for return airmail expresspost shipping (US$91 total), regardless of how many
parts are sent. Whether your parts work or not after processing, they
will be returned to you. CONTACT US FIRST, by phone (250) 769-1834,
or email. We will advise if enough parts can be
grouped to do a batch, and if you are in time to join that batch.

We will mark every part received, and generally your exact chip is the
one returned to you, but the processor in Japan may simply return the right number of
good working parts to us. If you wish to add your own marks, avoid
damaging the part, or using anything that will be removed by solvent
or other cleaners. If we feel the part is simply unsuitable for
repair (mechanically damaged, etc.), we will return it to you using
your US$21 shipping charge.

We will try and post into the Tek user's group at least 2 weeks before we are
assembling a batch for processing, but parts should be sent as soon as you have them ready,
to avoid any delays. There is never a benefit in waiting to ship them.

OVERVIEW: The CRT image has a strange center or side twist that gets worse as you move to one area (usually up or down), or is bad in all areas. This effect occurs at all sweep speeds, and is the classic appearace of a broken CRT, where the internal glass supports have been broken though rough shipping (typically dropped) and the deflection plates are now distorted. There is only one fix, CRT replacement, and possibly filing a shipping insurance claim for damage in transit.

SERVICE TOPIC: Tek CRT Replacement in the 2235

OVERVIEW: The CRT for the 2235 scope is not common, and can be a serious service problem if it fails.The original CRT (154-0861-00) can be substituted by another, more easily obtained Tek tube under some conditions. Details are below.

Date:
From: Ben ClarkTektronix 2235 CRT Replacement If you don't manage to find a 154-0861-00 CRT then in most cases you can use a 154-0731-00 tube from a 465/465B/468 which is much more likely to be available.

However there are a couple of caveats - The 0731 does not have integrally mounted trace rotation coils so
the ones from the old CRT must be swapped over to the new tube.

Pin 12 on the CRT socket must be reading approx 100v, an early 2235
will have this voltage but the voltage will be missing on later units.

If the voltage is missing, to successfully use the 0731 you must add 3 components: CR879, R879 and C879.
The mounting holes for these should already be drilled in the pcb
(under the power supply cover) and they should show on the silk screen
print so adding them is easy. Values are R879 510K 5% 0.25w, C879 Ceramic
0.1uF 200v, CR879 is 400v 750mA and has a Tek part number of 152-0413-00,
shown as manufacturer's part number UTR307, but I have successfully used UF4007, or even the slower 1N4004 in this
position. If the components are missing then most likely the wire between the circuit board and pin 12 of the CRT socket is also missing.
Some additional notes from Denis:
Also a note on the 2235 CRT from Ben - the 154-0861-00 or -10 are used as a
common CRT in the following models 2213A,2215A,2220,2221(A), 2230,2235,2236(A),2224 2232 so are often more common than 465 tubes (although experience in North America is usually the other way around, with the 465 tube being the common one due to decades of use). They are also normally much sharper than the 465/B CRT so I only like to swap them backwards. They also work in the 2213/2215 but you need to modify the PDA lead to suit the small spade terminal on the HV Multiplier. Added note: This also means you can probably work a substitution backwards in all the models above if no alternative tube can be found.

SERVICE TOPIC: No plug-in lights on the 7603 Mainframe

OVERVIEW: The Tek 7000 series plugs-ins with lighted pushbuttons do not light in the 7603 because there IS NO LIGHTING POWER sent to the plug in connections. For reasons that remain a mystery to us all, but presumably because the intended plug-ins (7A18, 7A26, 7B53A, etc.) simply did not require it, this connection is missing. In addition, the most common sweep plug-in used with the 7603, the 7B53A, looks like it has lighted pushbuttons, BUT IT DOES NOT. Net result? It is possible to route 5V lamp power to the plug-in slots, but it requires modifications to the frame, and will not light the 7B53A, no matter what you do.

Date: August 27, 2004 From: Rolynn PRECHTL, K7DFW
There is a very simple modification that can supply power to the plug-ins, as detailed below, but this IS NOT the method used by Tek in their mod kit.
Here is the easy fix from Rolynn:

I've done multiple units the cheap and dirty way. No additional regulator,
no pulling the LVPS to find a place to add extra components and the best
part, no cost.
Look for P90 and P10 on the rear edge of the Main Interface circuit board (left side
when viewed from the front).Connect P10-1 (gnd) to P90-7 or 8 (gnd).Connect P10-2 (+5V) to P90-4 (+5V).
Two wires and you're done. I have experienced no problems with the extra current demand from the +5V
regulated supply.

The 040-0686-01 mod kit for 7600 series plugin lamps uses an LM309K (presumably a 7805 would also work)
between +8 volts in the mainframe and +5 delivered to the plugin
compartments for lamp power. Derating of the range of acceptable line
voltages and operating temperature of the scope are required if the
total plugin lamp current exceeds 1.5 amps. You just add up the lamp
current requirements of each plugin to see if it exceeds 1.5 amps to
know if you have to derate line voltage or temperature specs. The
total kit instructions are on 7 pages of microfiche and installation
instructions and a parts list are included along with a derating
chart. I can provide hard copies of the instructions for 50 cents
per page plus $1 for postage(total = $4.50).

Stan

SERVICE TOPIC: 465M, Mis-Operation & Shipping Problems

OVERVIEW: Often, the problem with a complex scope is mis-operation or the result of recent shipping. Here's some useful info to keep you out of trouble with that freshly arrived, multi-mode triggered scope. Some models like the 465M pictured to the left have recurring problems, so it helps to know about them in advance.

Date:
From: WalterShipping problems ALWAYS CHECK THE OPERATING VOLTAGE BEFORE TURNING ON A NEWLY ARRIVED SCOPE!
-This sounds obvious, but people forget that the rear voltage changeover switch can be set to different voltages, and sometimes it can be accidentally changed during packing or unpacking. This is especially important if buying a scope from North America (110V) for use elsewhere, as the line voltage is almost certain to be wrong in a dangerous way. Often a fuse change is also required before use at local 220V or 230V power.

There are some common problems that show up with certain Tektronix scopes after shipping. See if any of these problems seem familiar to you:

Crooked CRT Trace - Adjust the TRACE ROTATION pot, usually by or under the CRT on most portables, sometimes on the back (5000 series) or internal (7603, etc.)

Loss of Trace Positioning, Moves only over half the screen.
-This is often caused by a deflection plate wire pulling loose from the neck of the CRT,
common on the 2200 series (very tight wire connection), but can occur on virtually all 400 series portables, and sometimes on the large 7000 series frames if the connections were loose. Not uncommon after rough shipping. Just remove the cover, and with all power OFF, replace the wire(s).

Loose Modules in the 465M, ALWAYS inspect before powering ON!
-The 465M modular design is great (Vertical, CRT, Motherboard and Horizontal), and much easier to work on than the 465 or 465B, BUT it is easily destroyed just by leaving a few screws out. It is very common for this model to have been put back together with missing screws, and often missing support plates or top covers when sold surplus, or on ebay. The result is severe stress applied to the very small bottom mating connectors of the modules during shipping. This often breaks the end off the small edge connector, and then mis-aligns the pins, sometimes shorting every single pin together. If powered up in this way, the scope can be severely damaged, so ALWAYS open and visually inspect any newly arrived 465M for that problem before applying power. Replace any missing top mounting screws, plates, etc., and replace any damaged connectors before operation.

Operating problems Watch out for the AC/GND/DC Input Switch!-The single most common operating problem is to accidentally move this switch (usually to GND) when changing vertical settings or connecting an input cable. The result is NO input signal displayed! Well, just put it to AC or DC coupling as required, and all will be well. Can't see the trace? PRESS BEAM FIND, it should appear, as it defeats many control settings. You may discover you have the trace positioned off screen, or have no sweep running.

Learn how the Trigger Controls Work!
-This is the next big pitfall, and usually results in NO trace displayed. Tek scopes have very complex triggering, and it's easy to pick a control setting that does not trigger the sweep. To begin, use INTernal triggering, AUTO triggering, DC coupling, MAIN sweep and adjust the trigger level for a stable display and a TRIGgered light. You can rove from there.

How to Take the Scope Apart! For virtually any CRT model that has a front rotating handle, the case is a shell (with handle attached). WITH POWER COMPLETELY DISCONNECTED, you can slide the case off (usually pulls to the rear, or the scope pulls forward, as you prefer) after removing the feet (or the plastic end cap with feet molded in) on the rear apron. The rear retainer (usually a ring around the rear of the case) will come off, making it possible to slide the case cover off. On 2200 and 2400 series scopes, There is only the plastic end cap, but there will also be a screw (Torx) or two through the cover which also have to be removed.

The 465M has a different cover style. It was designed to open with a quarter (a screwdriver or other coin also works), just rotate all the circular quarter-turn locking fasteners around the bottom edge of the case, and the case top pulls up and off.

5000 and 7000 series scopes have 3 case panels, right and left sides, and the bottom. The side panels have quarter-turn fasteners, rotate them, and the cover can be popped off. This is sometimes tricky to do, as the top edges are spring loaded into mating case slots, but a bit of downward pressure will usually pop the cover free. The bottom cover is secured by screws, often through the hold down retainers for the scope cart.

SERVICE TOPIC: Troubleshooting 465 Sweep Problems

OVERVIEW: The Tek 465 has many interdependent functions, so knowing where to start with a service problem can sometimes be puzzling. Here is a very good sequential technique from Denis to lead you clearly to the solution. This info applies to many Tek scopes of this era, so check to see if it will help your other models as well.

Date: May 21, 2004 From: Denis CobleyTektronix 465 - no horizontal time base on both channels As always - check all the power supplies first (-8, +5 +15 +50, +110). The 50V is the reference supply in most Tek scopes of that vintage including the 7k series - if that one is bad then all the others will also show bad.

Next - check for a 1000uF axial electrolytic cap in the middle of the main board - they often go shorted and take out a 22R feed resistor from the -8V supply.

Next - put the scope in XY mode and see if you can move the spot
horizontally to both extremes of the CRT - if yes the Horz output circuit is
fine.

Next - set the sweep to 0.5 seconds /div, turn the scope off then back on
(within 3 seconds) - if you see a single sweep only, then the sweep circuit
is working but you have a problem in the sweep logic not rearming after a
sweep (not seeing the Auto sweep pulse from the Trigger/Sweep logic circuit.
If you get a good sweep but it's missing on several settings or just A or B
sweep then you need to check those functions separately.

Check for burned / dirty timebase switch contacts, bad Sweep FET's (swap A to B to identify bad FET - both on Main board within 2" of each other. Check for "Green" 1W resistors - these often go bad or open circuit and there are some in the sweep circuit in some model/serial numbers. It's not possible to drill deeper until you get the above done - then you can concentrate on the sub circuit which is faulty. Good luck - it can take several hours to resolve sweep faults.

SERVICE TOPIC: TDS500 Series Capacitor Failures

OVERVIEW: The Tek TDS500 series like the TDS540, used first generation surface mount technology with some tempermental parts. Early surface mount electrolytics were very poor quality, basically regular electrolytic cans with a bottom spacer, and they leaked after being IR reflow soldered, as the heat was simply too high to maintain the can seal. Here's the whole story, and how to fix it.

Date: May 17, 2004 From: Denis CobleyWhat happens: TDS540 and similar models have the troublesome surface mount electrolytics on the data acquisition board. Once they begin to leak, the board can be severely damaged, and possibly unrepairable if left too long. These scopes were FACTORY SERVICE only, with no service manuals or parts readily available in the field. As a result, most people have little knowledge of the inner workings of these models, or any failure modes or history.

If you have the original can style capacitors, you will have to replace ALL of them - This is the best preventative measure, even if the unit is still working.

DOWNLOAD the complete illustrated summary of this fault from Denis, it is an MS Word Document. The locations and functions of the data acquisition sections are explained, along with the capacitor locations and values. Depending on your browser type, you may have to use save target as, to get the document when you click on the link.

SERVICE TOPIC: CRT Problems and Cross-References

OVERVIEW: The CRT is the heart of any analog scope, and there can be many different issues that create a visible problem on the CRT. Before you change the tube, read over these service suggestions. A model and part cross reference is also provided for some older tube types.

Date:
From: WalterTektronix CRT IssuesHaving CRT problems with your Tek scope? check this info first before changing the tube:
Assuming you have correct CRT gun bias (look in the manual, and don't skip this adjustment!), and have looked at the horizontal and vertical drive signals, and they are UNDISTORTED, then:

Odd waveform distortion (humps, curves, sudden angles) that is in the
same physical place on the CRT (regardless of control settings)
especially of very unusual shape, is generally caused by:

1.Magnetic Interference: this can be from accidentally magnetized parts
within the CRT, adjacent hardware or an external source. Move the
scope, if the interference is unchanged, degauss the tube and chassis
with a standard TV degaussing coil (or any home made one excited by
AC, very easy to make). If this improves matters, keep looking for the exact offending
part, and degauss again, or remove the hardware that is magnetized.
You can usually cure this problem, but it is time consuming. Severe
magnetic distortion can be caused by a single magnetized screw in the
wrong place. Don't sit a scope on top of a speaker cabinet or by
speakers, or near anything with a magnetron in it, the results can
be serious. MANY types of microwave test gear have strong magnets internally so check the position of these items first. Fans are also notorious for their strong external magnetic field, as are other magnetically deflected displays like computer monitors, TVs and CCTV displays.

2.Mechanical distortion within the tube: if the above technique
doesn't work, the tube or the scope has probably been dropped, and the
shock has broken or bent an internal electrode or support. If the
tube exhibits the identical distortion outside the chassis, with the
shield removed, it is damaged, and has to be replaced.

Other CRT issues:

3. If the display is crooked relative to the graticule lines (goes at
an angle), this is almost always the trace rotation adjustment, which
may not be easy to find or readily accessible in some models.
Generally, it is DC bias applied to a coil around the CRT neck, you
may be able to find the control by following the coil wires back to
the PC board. In many Tek models, it is at the front by the CRT itself, in the 5000 scope series, it is a pot on the rear panel. It is VERY common for this to be out of adjustment
after shipping. Calibration is not affected by this adjustment.

4. If the display is turned up or down at the corners, or has an angled
appearance, it is probably the geometry adjustment, and this can be
complex to set, you must use the manual and follow the CRT alignment
carefully. Calibration is affected. Some scopes have supplemental X
or Y axis alignment as well, generally via coils.

5. If strange trace effects occur at the face of the tube when touched,
it probably indicates high static build up on the display filter, or
tube face. Clean the parts, then wipe everything down with a
standard anti-static wipe, the effect will disappear. Plastic can be
very highly charged when rubbed with a synthetic cloth for cleaning.
Use a damp cotton cloth or anti-static wipe to avoid this effect

IMPORTANT !Graphical logos and trademarks are the property of their respective owners, including Tektronix, Fluke, RCA, TI, GE, General Radio and Hewlett Packard, and are used here merely to unambiguously identify the products. Sphere Research IS NOT a factory authorized distributor for any of the product lines indicated.